Organic light emitting diode display having auxiliary electrode

ABSTRACT

In an aspect, an organic light emitting diode display including: a substrate; a first electrode and an auxiliary electrode positioned on the substrate and separated from each other; an absorption electrode positioned on the auxiliary electrode; an organic emission layer positioned on the first electrode and having a contact hole exposing the auxiliary electrode and the absorption electrode; and a second electrode positioned on the organic emission layer and connected to the auxiliary electrode and the absorption electrode through the contact hole is provided. In an aspect, the organic light emitting diode (OLED) display may minimize the voltage drop of the driving power passing through the large-sized electrode of the thin film for driving the organic emission layer, and may simplify the removal process of the organic emission layer on the auxiliary electrode by adding the absorption electrode on the auxiliary electrode.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. For example, this application is a divisional of U.S. patentapplication Ser. No. 14/205,088, filed Mar. 11, 2014, which claimspriority to and the benefit of Korean Patent Application No.10-2013-0122831 filed in the Korean Intellectual Property Office on Oct.15, 2013, each disclosure of which is incorporated herein by referencein its entirety.

BACKGROUND

1. Field

This disclosure relates to an organic light emitting diode display and amanufacturing method thereof For example, the present disclosure relatesto an organic light emitting diode display including an auxiliaryelectrode and an absorption electrode.

2. Description of the Related Technology

An organic light emitting diode (OLED) display has been recentlyspotlighted as a display device for displaying images.

A conventional OLED display typically includes a first electrode, anorganic emission layer disposed on the first electrode, and a secondelectrode disposed on the organic emission layer.

An OLED display may be classified into a front emission type, a rearemission type, and a dual emission type. The front emission type OLEDdisplay typically has a structure in which a second electrode of anorganic light emitting element is formed over the entire area of asubstrate where the organic light emitting element is formed in a thinfilm shape in order to minimize deterioration of luminance of lightgenerated from an organic emission layer.

However, a voltage drop may occur in driving power passing through thesecond electrode for driving the organic emission layer due toelectrical resistance of the second electrode since the second electrodeformed as a thin film is formed over the entire area of the substrate inthe front emission type of OLED display.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the disclosure andtherefore it may contain information that does not form the prior artthat is already known to a person of ordinary skill in the art.

SUMMARY

Some embodiments provide an organic light emitting diode (OLED) displaythat can minimize a voltage drop in driving power passing through alarge-sized thin film electrode for driving an organic emission layerand can simplify a removal process of the organic emission layer on anauxiliary electrode by adding an absorption electrode on the auxiliaryelectrode, and a manufacturing method thereof.

Some embodiments provide an organic light emitting diode displayincluding: a substrate; a first electrode and an auxiliary electrodepositioned on the substrate and separated from each other; an absorptionelectrode positioned on the auxiliary electrode; an organic emissionlayer positioned on the first electrode and having a contact holeexposing the auxiliary electrode and the absorption electrode; and asecond electrode positioned on the organic emission layer and connectedto the auxiliary electrode and the absorption electrode through thecontact hole.

In some embodiments, the second electrode may contact an etched surfaceof the contact hole, an upper surface of the auxiliary electrode, and anupper surface and a side surface of the absorption electrode.

In some embodiments, the absorption electrode may be made of oneselected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium(Cr).

In some embodiments, the absorption electrode may be formed of a singlelayer or multiple layers.

In some embodiments, the absorption electrode may have a thickness of300-1500 Å when the absorption electrode is formed of a single layer.

In some embodiments, an oxide layer may be further formed between theabsorption electrode of the multiple layers when the absorptionelectrode is formed of multiple layers.

In some embodiments, the absorption electrode may be formed of duallayers, and an upper layer and a lower layer of the absorption electrodemay respectively have thicknesses of 40-100 Å and 300-1000 Å.

In some embodiments, the oxide layer may be ITO or IZO.

In some embodiments, the absorption electrode may be formed with a lineshape or a dot shape in a direction parallel to the auxiliary electrodeon the auxiliary electrode.

In some embodiments, the organic light emitting diode display mayfurther include: a gate line positioned on the substrate; a data lineand a driving voltage line insulated from and intersecting the gate lineand separated from each other; a switching thin film transistorconnected to the gate line and the data line; and a driving thin filmtransistor connected to the switching thin film transistor and thedriving voltage line, wherein the first electrode may be connected to adrain electrode of the driving thin film transistor.

Some embodiments provide an organic light emitting diode displayincludes: a substrate; a first electrode and an absorption electrodemade of one selected from molybdenum (Mo), titanium (Ti), tungsten (W),and chromium (Cr), positioned on the substrate and separated from eachother; an organic emission layer positioned on the first electrode and acontact hole exposing the absorption electrode; and a second electrodepositioned on the organic emission layer and connected to the absorptionelectrode through the contact hole, wherein the absorption electrode isconnected to the second electrode thereby having a function of anauxiliary electrode of the first electrode.

Some embodiments provide a manufacturing method of an organic lightemitting diode display includes: forming a thin film transistor on asubstrate; forming a first electrode connected to the thin filmtransistor and an auxiliary electrode separated from the firstelectrode; forming an absorption electrode on the auxiliary electrode;forming an organic emission layer on the first electrode, the auxiliaryelectrode, and the absorption electrode; irradiating an energy lightsource to the organic emission layer to etch the organic emission layer,thereby forming a contact hole having an opening exposing the auxiliaryelectrode and the absorption electrode; and depositing a metal layer onthe organic emission layer to form a second electrode contacting anupper surface of the auxiliary electrode, an upper surface of theabsorption electrode, and an etched surface of the opening in thecontact hole.

In some embodiments, the etching of the organic emission layer may use alaser, a flash lamp, or a tungsten halogen lamp as an energy lightsource.

In some embodiments, the organic light emitting diode (OLED) display mayminimize the voltage drop of the driving power passing through thelarge-sized electrode of the thin film for driving the organic emissionlayer, and may simplify the removal process of the organic emissionlayer on the auxiliary electrode by adding the absorption electrode onthe auxiliary electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of a pixel circuit of an organic lightemitting diode display according to an exemplary embodiment.

FIG. 2 is a layout view of one pixel of the organic light emitting diodedisplay of FIG. 1.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2.

FIG. 4 is a layout view of one pixel of an organic light emitting diodedisplay according to another exemplary embodiment.

FIG. 5 is a layout view of one pixel of an organic light emitting diodedisplay according to another exemplary embodiment.

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5.

FIGS. 7 to 13 are cross-sectional views sequentially showing amanufacturing method of an organic light emitting diode displayaccording to another exemplary embodiment.

FIG. 14 is a graph showing a result of measuring absorbency according toa wavelength of light source energy for an absorption electrode that isformed of a single layer.

FIG. 15 is a graph showing a result of measuring absorbency according toa wavelength of light source energy for an absorption electrode that isformed of multiple layers.

DETAILED DESCRIPTION

The present disclosure will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present embodiments.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

An organic light emitting diode display and a manufacturing methodthereof according to an exemplary embodiment will be described withreference to accompanying drawings.

FIG. 1 is a circuit diagram of a pixel circuit of an organic lightemitting diode display according to an exemplary embodiment.

As shown in FIG. 1, an organic light emitting diode display according tothe exemplary embodiment includes a plurality of signal lines 121, 171,and 172 and a plurality of pixels (PX) connected thereto and arranged inan approximate matrix form.

The signal lines include a plurality of gate lines 121 transferring agate signal (or a scan signal), a plurality of data lines 171transferring a data signal, and a plurality of driving voltage lines 172transferring a driving voltage Vdd. The gate lines 121 extend in anapproximate row direction and are almost parallel to each other, andvertical direction portions of the data lines 171 and the drivingvoltage lines 172 extend in an approximate column direction and arealmost parallel to each other.

Each pixel PX includes a switching thin film transistor Qs, a drivingthin film transistor Qd, a storage capacitor Cst, and an organic lightemitting diode (OLED) 70.

The switching thin film transistor Qs has a control terminal, an inputterminal, and an output terminal, the control terminal is connected tothe gate line 121, the input terminal is connected to the data line 171,and the output terminal is connected to the driving thin film transistorQd. The switching thin film transistor Qs transfers the data signalapplied to the data line 171 to the driving thin film transistor Qd inresponse to the scan signal applied to the gate line 121.

Further, the driving thin film transistor Qd has a control terminal, aninput terminal, and an output terminal, and the control terminal isconnected to the switching thin film transistor Qs, the input terminalis connected to the driving voltage line 172, and the output terminal isconnected to the organic light emitting diode 70. The driving thin filmtransistor Qd allows an output current (ILD) having a varying magnitudeaccording to a voltage applied between the control terminal and theoutput terminal to flow.

The capacitor Cst is connected between the control terminal and theinput terminal of the driving thin film transistor Qd. This capacitorCst charges the data signal applied to the control terminal of thedriving thin film transistor Qd and maintains the data signal after theswitching thin film transistor Qs is turned off.

The organic light emitting diode LD has an anode connected to the outputterminal of the driving thin film transistor Qd, and a cathode connectedto a common voltage Vss. The organic light emitting diode (LD) displaysan image by emitting light while changing the intensity thereofaccording to the output current (ILD) of the driving thin filmtransistor Qd.

Further, the connection relationship of the thin film transistors Qs andQd, the capacitor Cst, and the organic light emitting diode 70 may bechanged.

The organic light emitting diode display in which the second electrodeas a thin film type is entirely formed on the substrate including theorganic light emitting element uses an auxiliary electrode forming thesecond electrode to prevent generation of a voltage drop to a powersource passing through the second electrode to drive the organicemission layer by electric resistance of the second electrode.

However, a process of removing an organic layer to contact the auxiliaryelectrode and the first electrode is required and energy absorbency ofthe organic layer is low such that energy transmitting efficiency islargely decreased, and the removal process must be performed in a vacuumcondition.

Next, an organic light emitting diode display according to an exemplaryembodiment of the present invention will be described with reference toFIG. 2 and FIG. 3.

FIG. 2 is a layout view of one pixel of the organic light emitting diodedisplay of FIG. 1, and FIG. 3 is a cross-sectional view taken along theline III-III of FIG. 2.

As shown in FIG. 3, a buffer layer 120 is formed on a substrate 100.

In some embodiments, the substrate 100 may be an insulating substratemade of glass, quartz, ceramic, or a polymer material, or the substrate100 may be a metallic substrate made of a stainless steel. In someembodiments, the polymer material may be an organic material selectedfrom a group consisting of polyethersulfone (PES), polyacrylate (PAR),polyetherimide (PEI), polyethylene naphthalate (PEN), polyethyleneterephthalate (PET), polyphenylene sulfide (PPS), polyallylate,polyimide, polycarbonate (PC), cellulose triacetate (TAC), and celluloseacetate propionate (CAP) that are insulating organic materials.

In some embodiments, the buffer layer 120 is formed on the substrate100.

In some embodiments, the buffer layer 120 may be formed to have astructure of a single layer of a silicon oxide (SiOx) or a siliconnitride (SiNx), or a plurality of layers where a silicon nitride (SiNx)and a silicon oxide (SiOx) are laminated. The buffer layer acts toprevent unnecessary components such as an impurity or moisture frompermeating, and planarizes the surface.

In some embodiments, a first semiconductor 135 a and a secondsemiconductor 135 b may both be made of polysilicon and a firstcapacitor electrode 138 are formed on the buffer layer 120.

In some embodiments, the first semiconductor 135 a and the secondsemiconductor 135 b may be divided into channel regions 1355 a and 1355b, and source regions 1356 a and 1356 b and drain regions 1357 a and1357 b respectively formed on both sides of the channel regions 1355 aand 1355 b. In some embodiments, the channel regions 1355 a and 1355 bof the first semiconductor 135 a and the second semiconductor 135 b arepolysilicon into which impurities have not been doped, that is,intrinsic semiconductors. In some embodiments, the source regions 1356 aand 1356 b and the drain regions 1357 a and 1357 b of the firstsemiconductor 135 a and the second semiconductor 135 b are polysiliconinto which conductive impurities have been doped, that is, impuritysemiconductors.

In some embodiments, the impurities dopes into the source regions 1356 aand 1356 b, the drain regions 1357 a and 1357 b, and the first capacitorelectrode 138 can be either p-type impurities or n-type impurities.

In some embodiments, a gate insulating layer 140 is formed on the firstsemiconductor 135 a, the second semiconductor 135 b, and the firstcapacitor electrode 138. In some embodiments, the gate insulating layer140 can be a single layer or a plurality of layers including at leastone of tetraethyl orthosilicate (TEOS), a silicon nitride (SiNx), and asilicon oxide (SiO_(x)).

In some embodiments, the gate line 121, a second gate electrode 155 b,and a second capacitor electrode 158 are formed on the gate insulatinglayer 140.

In some embodiments, the gate line 121 (shown in the perspective of FIG.2) lengthily extends in a horizontal direction and transfers a gatesignal, and includes a first gate electrode 155 a that is protruded fromthe gate line 121 to the first semiconductor 135 a.

In some embodiments, the first gate electrode 155 a and the second gateelectrode 155 b overlap the respective channel regions 1355 a and 1355b, and the second capacitor electrode 158 overlaps the first capacitorelectrode 138.

In some embodiments, each of the second capacitor electrode 158, thefirst gate electrode 155 a, and the second gate electrode 155 b can havea single layer of a plurality of layers made of molybdenum, tungsten,copper, aluminum, or an alloy thereof.

In some embodiments, the first capacitor electrode 138 and the secondcapacitor electrode 158 form a capacitor Cst using the gate insulatinglayer 140 as a dielectric material.

In some embodiments, a first interlayer insulating layer 160 is formedon the first gate electrode 155 a, the second gate electrode 155 b, andthe second capacitor electrode 158. In some embodiments, the firstinterlayer insulating layer 160, like the gate insulating layer 140, canbe made of tetraethyl orthosilicate (TEOS), a silicon nitride (SiNx), ora silicon oxide (SiO_(x)).

In some embodiments, the first interlayer insulating layer 160 and thegate insulating layer 140 include a source contact hole 166 and a draincontact hole 167 through which the source regions 1356 a and 1356 b andthe drain regions 1357 a and 1357 b are exposed, respectively.

In some embodiments, the data lines 171 including a first sourceelectrode 176 a, the driving voltage lines 172 including a second sourceelectrode 176 b, a first drain electrode 177 a (not shown), and a seconddrain electrode 177 b are formed on the first interlayer insulatinglayer 160.

In some embodiments, the data line 171 transmits a data signal andextends in a direction crossing the gate line 121.

In some embodiments, the driving voltage line 172 transmits apredetermined voltage, and extends in the same direction as that of thedata line 171 while being separated from the data line 171.

In some embodiments, the first source electrode 176 a protrudes towardthe first semiconductor 135 a from the data line 171, and the secondsource electrode 176 b protrudes toward the second semiconductor 135 bfrom the driving voltage line 172. In some embodiments, the first sourceelectrode 176 a and the second source electrode 176 b are connected withthe source regions 1356 a and 1356 b through the source contact holes166, respectively.

In some embodiments, the first drain electrode 177 a (not shown) facesthe first source electrode 176 a and is connected with the drain region1357 a through the drain contact hole 167.

The first drain electrode 177 a (not shown) extends along the gate line,and is electrically connected with the second gate electrode 158 bthrough a contact hole 81.

In some embodiments, the second drain electrode 177 b is connected withthe drain region 1357 b through the drain contact hole 167.

In some embodiments, the data line 171, the driving voltage line 172,and the first drain electrode 177 a may be formed as a single layer or amultilayer formed of a low resistance material, such as Al, Ti, Mo, Cu,Ni, or an alloy thereof, or a corrosion resistant material. For example,the data line 171, the driving voltage line 172, and the first drainelectrode 177 a may be triple layers of Ti/Cu/Ti or Ti/Ag/Ti.

In an exemplary embodiment, the capacitor may be formed by overlappingthe first capacitor electrode and the second capacitor electrode, butthe capacitor having a metal/dielectric/metal structure may be formed byforming an electrode on the same layer as that of the data line or thesame layer as that of the first electrode.

In some embodiments, a second interlayer insulating layer 180 is formedon the data line 171, the driving voltage line 172, the first drainelectrode 177 a (not shown), and a first electrode 710.

In some embodiments, the first electrode 710 and an auxiliary electrode740 are formed on the second interlayer insulating layer 180.

The first electrode 710 may be an anode of the organic light emittingelement of FIG. 1. In some embodiments, the first electrode 710 isconnected to the second drain electrode 177 b through a contact hole 82.

In an exemplary embodiment, the second drain electrode 177 b and thefirst electrode 710 are connected through the contact hole 82 with thesecond interlayer insulating layer 180 interposed therebetween, but thesecond drain electrode 177 b and the first electrode 710 may beintegrally formed.

In some embodiments, the auxiliary electrode 740 is separated from thefirst electrode 710, overlaps at least one of the data line 171 and thedriving voltage line 172, and is elongated along with them. In someembodiments, the auxiliary electrode 740 may be applied with the samevoltage as a second electrode 730 to reduce the voltage drop of thesecond electrode 730.

In some embodiments, an absorption electrode 770 is formed on theauxiliary electrode 740.

In some embodiments, the auxiliary electrode 740 is generally connectedto the second electrode 730, and to connect the auxiliary electrode 740and the second electrode 730 to each other, an organic emission layer720 disposed between the auxiliary electrode 740 and the secondelectrode 730 must be removed. In this configuration, the organicemission layer 720 has the low energy absorbency and the energytransmission efficiency is largely decreased such that the absorptionelectrode 770 easily absorbs the energy by being disposed between theorganic emission layer 720 and the auxiliary electrode 740, and therebythe organic emission layer 720 may be further simply removed by a methodof vaporizing the organic emission layer 720 by increasing thetemperature of the organic emission layer 720.

In some embodiments, the absorption electrode 770 absorbs the energywhen removing the organic emission layer 720 such that a material forthe absorption electrode 770 must have the high energy absorbency, andthe absorption electrode 770 is disposed between the auxiliary electrode740 and the second electrode 730 such that the material must haveconductivity for an electrical connection between the auxiliaryelectrode 740 and the second electrode 730.

Accordingly, the absorption electrode 770 may be a metal material havinghigh absorbency and conductivity and may be formed of one selected frommolybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr).

In some embodiments, the absorption electrode 770 may be formed with athickness of 300-1500 Å, and the energy absorbency is excellent in thisrange.

In some embodiments, the absorption electrode 770 may be formed of thesingle layer or the multiple layers.

When the absorption electrode 770 is formed of a plurality layers, anoxide layer (not shown) may be formed between a plurality of absorptionelectrodes 770.

In some embodiments, the oxide layer may be one selected from ITO orIZO, and may have a thickness of 400-800 Å.

Among the absorption electrode 770 of the plurality of layers, a lowerlayer may be thicker than an upper layer, and the upper layer of athickness of 40-100 Å and the lower layer of a thickness of 300-1000 Åmay be formed.

In some embodiments, a pixel definition layer 116 patterned with aninsulating material exposing at least a portion of the first electrode710 and the auxiliary electrode 740 and the entire portion of theabsorption electrode 770 is formed on the entire substrate including thefirst electrode 710, and the organic emission layer 720 including anemission layer is formed on the pixel definition layer 116 formed on theentire substrate including the first electrode 710 and the exposedportion of the first electrode 710. In some embodiments, the organicemission layer 720 includes a contact hole 74 exposing the auxiliaryelectrode 740 and the absorption electrode 770.

As shown in the exemplary embodiment of FIG. 2, a plurality of contactholes 74 are disposed with a uniform interval, however it may beelongated along with the auxiliary electrode 740.

In some embodiments, the organic emission layer 720 may be formed of alow molecular weight organic material or a high molecular weight organicmaterial such as PEDOT ((poly)3,4-ethylenedioxythiophene). Further, theorganic emission layer 720 may be formed of a multilayer including oneor more of a hole injection layer (HIL), a hole transport layer (HTL),an electron transport layer (ETL), and an electron injection layer(EIL), and the emission layer. When all the layers are included, thehole injection layer (HIL) is disposed on the first electrode 710 as theanode, and the hole transport layer (HTL), the emission layer, theelectron transport layer (ETL), and the electron injection layer (EIL)are sequentially laminated thereon.

In the organic emission layer 720, a red organic emission layer, a greenorganic emission layer, and a blue organic emission layer may belaminated in a red pixel, a green pixel, and a blue pixel, respectively,and a red color filter, a green color filter, and a blue color filtermay be formed for each pixel to embody a color image. As anotherexample, a white organic emission layer emitting light having a whitecolor may be formed in all of the red pixel, the green pixel, and theblue pixel, and the red color filter, the green color filter, and theblue color filter may be formed for each pixel to embody the colorimage.

For the organic emission layer 720 according to the present invention,the lamination structures of the red pixel, the blue pixel, and thegreen pixel are the same. Accordingly, a deposition mask for depositingthe organic emission layer on each pixel, that is, the red pixel, thegreen pixel, and the blue pixel, may not be used.

The white organic emission layer described as another example may beformed of one organic emission layer, and even includes a constitutionwhere a plurality of organic emission layers are laminated to emit lighthaving the white color. For example, a constitution where at least oneyellow organic emission layer and at least one blue organic emissionlayer are combined to emit light having the white color, a constitutionwhere at least one cyan organic emission layer and at least one redorganic emission layer are combined to emit light having the whitecolor, or a constitution where at least one magenta organic emissionlayer and at least one green organic emission layer are combined to emitlight having the white color may be included.

In some embodiments, the second electrode 730 is formed on an opening 99exposing the organic emission layer 720 and the contact hole 74.

In some embodiments, the second electrode 730 becomes a cathode of theorganic light emitting element. Accordingly, the first electrode 710 andthe absorption electrode 770, the organic emission layer 720, and thesecond electrode 730 form the organic light emitting element 70.

In some embodiments, the second electrode 730 contacts an upper surfaceof the auxiliary electrode 740, an upper surface and a side surface ofthe absorption electrode 770, and an etched surface of the opening 99 inthe contact hole 74.

In some embodiments, the organic light emitting diode display may haveany one structure among a top display type, a rear display type, and aboth-side display type according to a direction in which the organiclight emitting diode 70 emits light.

In the top display type of organic light emitting diode displayaccording to the exemplary embodiment, the first electrode 710 is formedas a reflective layer, and the second electrode 730 is formed as atransparent layer or a semi-transparent layer.

In some embodiments, the reflective layer and the semi-transparent layerare formed of at least one metal among magnesium (Mg), silver (Ag), gold(Au), calcium (Ca), lithium (Li), chromium (Cr), and aluminum (Al), oran alloy thereof. The reflective layer and the semi-transparent layerare determined by thickness, and the semi-transparent layer may beformed to have a thickness equal to or less than 200 nm. As thethickness is decreased, transmittance of light is increased, but whenthe thickness is excessively small, resistance is increased. In someembodiments, the transparent layer may be formed of a material such asindium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), orindium oxide (In₂O₃).

As described above, when forming the auxiliary electrode 740 and theabsorption electrode 770 that are connected to the second electrode 730,the voltage drop of the driving voltage passing through the secondelectrode 730 that is formed on the entire substrate 100 may beminimized and the contact hole 74 may be simply formed.

An organic light emitting diode display according to another exemplaryembodiment will be described with reference to FIG. 4.

FIG. 4 is a layout view of one pixel of an organic light emitting diodedisplay according to another exemplary embodiment of the presentinvention.

The exemplary embodiment shown in FIG. 4 is substantially the same asthe exemplary embodiment shown in FIG. 2 and FIG. 3, except for aformation position and a shape of the absorption electrode 770 such thatthe overlapping description of reference numerals is omitted.

As shown in the exemplary embodiment of FIG. 4, an absorption electrode771 of the organic light emitting diode display does not have the lineshape parallel to the auxiliary electrode 740, but the absorptionelectrode 771 may be formed with a dot shape on the auxiliary electrode740. In FIG. 4, a plurality of absorption electrodes 771 have aquadrangle shape, however the shape of the absorption electrode may bevarious such as triangle or a polygon.

An organic light emitting diode display according to another exemplaryembodiment will be described with reference to FIG. 5 and FIG. 6.

FIG. 5 is a layout view of one pixel of an organic light emitting diodedisplay according to the current exemplary embodiment of the presentinvention, and FIG. 6 is a cross-sectional view taken along the lineVI-VI of FIG. 5.

The exemplary embodiment shown in FIG. 5 and FIG. 6 is substantially thesame as the exemplary embodiment shown in FIG. 2 and FIG. 3, except thatthe auxiliary electrode 740 is replaced by the absorption electrode 770such that the overlapping description of reference numerals is omitted.

In some embodiments, the absorption electrode 770 is separated from thefirst electrode 710, overlaps at least one of the data line 171 and thedriving voltage line 172, and is elongated along with them. In someembodiments, the absorption electrode 770 with a function of theauxiliary electrode to reduce the voltage drop of the second electrode730 may be applied with the same voltage as the second electrode 730.

In some embodiments, the absorption electrode 740 is connected to thesecond electrode 730 to connect the absorption electrode 770 and thesecond electrode 730 to each other, the organic emission layer 720disposed between the absorption electrode 770 and the second electrode730 must be removed. In some embodiments, the organic emission layer 720has the low energy absorbency and the energy transmission efficiency islargely decreased such that the absorption electrode 770 easily absorbsthe energy by being disposed as the auxiliary electrode, and thereby theorganic emission layer 720 may be further simply removed by the methodof vaporizing the organic emission layer 720 by increasing thetemperature of the organic emission layer 720.

In some embodiments, the absorption electrode 770 absorbs the energywhen removing the organic emission layer 720 such that the material forthe absorption electrode 770 must have high energy absorbency, and theabsorption electrode 770 has the function of the auxiliary electrodesuch that the material must have conductivity for an electricalconnection between the absorption electrode 770 and the second electrode730.

Accordingly, the absorption electrode 770 may be the metal materialhaving the high absorbency and the conductivity and may be formed of oneselected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium(Cr).

In some embodiments, the absorption electrode 770 may be formed with athickness of 300-1500 Å, and the energy absorbency is excellent in thisrange.

In some embodiments, the absorption electrode 770 may be formed of thesingle layer or the multiple layers.

In some embodiments, an oxide layer (not shown) may be formed between aplurality of absorption electrodes 770 when the absorption electrode 770is formed of multiple layers.

In some embodiments, the oxide layer may be one selected from ITO orIZO, and may have a thickness of 400-800 Å.

In this configuration, among the absorption electrode 770 of theplurality of layers, a lower layer may be thicker than an upper layer,and the upper layer of a thickness of 40-100 Å and the lower layer of athickness of 300-1000 Å may be formed.

In some embodiments, the organic emission layer 720 is formed on theentire substrate including the first electrode 710. In some embodiments,the organic emission layer 720 includes the contact hole 74 exposing theabsorption electrode 770 functioning as the auxiliary electrode.

Next, a method manufacturing the organic light emitting diode displaywill be described in detail with reference to FIG. 7 to FIG. 13 as wellas FIG. 2 and FIG. 3.

FIGS. 7 to 13 are cross-sectional views sequentially showing amanufacturing method of an organic light emitting diode displayaccording to another exemplary embodiment of the present invention.

As shown in FIG. 7, the buffer layer 120 is formed on a substrate 100.In some embodiments, the buffer layer 120 may be formed of a siliconnitride or a silicon oxide.

After forming a polysilicon film on the buffer layer 120, the firstsemiconductor 135 a, the second semiconductor 135 b, and the firstcapacitor electrode 138 are formed by patterning the polysilicon film.

Next, as shown in FIG. 8, the gate insulating layer 140 may be formed onthe first semiconductor 135 a and the second semiconductor 135 b. Insome embodiments, the gate insulating layer 140 may be formed of asilicon nitride or a silicon oxide.

Furthermore, after stacking a metal film on the gate insulating layer140, the first and second gate electrodes 155 a and 155 b and the secondcapacitor electrode 158 are formed by patterning the metal film.

In some embodiments, the source region, the drain region, and thechannel region may be formed by doping conductive impurities into thefirst semiconductor 135 a and the second semiconductor 135 b by usingthe first gate electrode 155 a and the second gate electrode 155 b as amask. In some embodiments, prior to the formation of the first gateelectrode 155 a and the second gate electrode 155 b, the conductiveimpurities can also be doped into the first capacitor electrode 138using a photoresist film. Furthermore, if each of the first gateelectrode 155 a and the second gate electrode 155 b is formed of a duallayer and the second capacitor electrode 158 is formed of a singlelayer, the conductive impurities can also be doped into the firstcapacitor electrode 138 along with the source region and the drainregion.

As shown in FIG. 9, the interlayer insulating layer 160 having thecontact holes 166 and 167 through which the source region and the drainregion are respectively exposed is formed on the first and second gateelectrodes 155 a and 155 b and the second capacitor electrode 158. Insome embodiments, the interlayer insulating layer 160 can be made oftetraethyl orthosilicate (TEOS), a silicon nitride, or a silicon oxide.Furthermore, the interlayer insulating layer 160 can be made of a lowdielectric constant material in order to make the substrate flat.

Next, as shown in FIG. 10, ITO/Ag/ITO is deposited and patterned on theinterlayer insulating layer 160 to form the first electrode 710 and theauxiliary electrode 740.

Next, as shown in FIG. 11, the absorption electrode 770 is formed on theauxiliary electrode 740.

In some embodiments, the absorption electrode 770 absorbs the energywhen removing the organic emission layer 720 such that the material forthe absorption electrode 770 must have the high energy absorbency, andthe absorption electrode has the function of the auxiliary electrode 740such that the material must have conductivity for the electricalconnection between the absorption electrode 770 and the second electrode730.

Accordingly, the absorption electrode 770 may be the metal materialhaving the high absorbency and the conductivity and may be formed of oneselected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium(Cr).

In some embodiments, the absorption electrode 770 may be formed with athickness of 300-1500 Å, and the energy absorbency is excellent in thisrange.

In some embodiments, the absorption electrode 770 may be formed of thesingle layer or the multiple layers.

When the absorption electrode 770 is formed of multiple layers, an oxidelayer (not shown) may be formed between a plurality of absorptionelectrodes.

The oxide layer may be one selected from ITO or IZO, and may have athickness of 400-800 Å.

In this configuration, among the absorption electrode 770 of theplurality of layers, a lower layer may be thicker than an upper layer,and the upper layer of the thickness of 40-100 Å and the lower layer ofthe thickness of 300-1000 Å may be formed.

In some embodiments, the absorption electrode 770 may be formed with theline shape parallel to the auxiliary electrode 740, as shown in FIG. 4,may be formed with the dot shape on the auxiliary electrode 740.

In some embodiments, the absorption electrode 770 absorbs the energywhen removing the organic emission layer 720 such that the material forthe absorption electrode 770 must have the high energy absorbency, andthe absorption electrode 770 is disposed between the auxiliary electrode740 and the second electrode 730 such that the material must haveconductivity for an electric connection between the auxiliary electrode740 and the second electrode 730.

Accordingly, the absorption electrode 770 may be a metal material havinghigh absorbency and conductivity and may be formed of one selected frommolybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr).

In some embodiments, the absorption electrode 770 may be formed with athickness of 300-1500 Å, and the energy absorbency is excellent in thisrange.

In some embodiments, the absorption electrode 770 may be formed of thesingle layer or the multiple layers.

When the absorption electrode 770 is formed of multiple layers, an oxidelayer (not shown) may be formed between a plurality of absorptionelectrodes 770.

The oxide layer may be one selected from ITO or IZO, and may have athickness of 400-800 Å.

At this time, among the absorption electrode 770 of the plurality oflayers, the lower layer may be thicker than the upper layer, and theupper layer of the thickness of 40-100 Å and the lower layer of thethickness of 300-1000 Å may be formed.

Next, as shown in FIG. 12, on the first electrode 710, the auxiliaryelectrode 740, and the absorption electrode 770, the pixel definitionlayer 116 patterned with the insulating material is formed to expose atleast a portion of the first electrode 710 and the auxiliary electrode740, and the entire absorption electrode 770, and the organic emissionlayer 720 is deposited on the pixel definition layer 116, the exposedfirst electrode 710, the auxiliary electrode 740, and the absorptionelectrode 770.

In some embodiments, the organic emission layer 720 is formed on theentire substrate without a separate mask, and a hole auxiliary layer, ared organic emission layer, a green organic emission layer, a blueorganic emission layer, and an electron auxiliary layer may besequentially deposited.

Next, a light source having energy having a wavelength region to beabsorbed into the absorption electrode 770 to etch the organic emissionlayer 720, and the second electrode 730 having the opening 99 exposingthe auxiliary electrode 740 and the absorption electrode 770 and thecontact hole 74, are formed.

Conventionally, a laser is used when etching the organic emission layer720, however, when manufacturing the organic light emitting diodedisplay according to an exemplary embodiment, the energy absorbency ofthe absorption electrode 770 is high such that a laser, a flash lamp, atungsten halogen lamp, etc., may be used as an energy light source usedto etch the organic emission layer 720.

In some embodiments, the energy irradiated by the light source is easilyabsorbed to the absorption electrode 770 such that the temperature ofthe absorption electrode 770 is increased, and at this time, the organicemission layer 720 formed on the absorption electrode 770 may be etchedby the method of increasing the temperature of the organic emissionlayer 720 and evaporating the organic emission layer 720.

In some embodiments of the manufacturing of the organic light emittingdiode display, the method of increasing the temperature of the organicemission layer 720 and evaporating the organic emission layer 720 byusing the absorption electrode 770 is performed in the etching processto form the opening 99 in the organic emission layer 720 such that apatterning mask for the etching of the organic emission layer 720 may beomitted.

Next, as shown in FIG. 13, a metal layer is formed on the entiresubstrate to form the second electrode 730 on the organic emission layer720 and connected to the auxiliary electrode 740 and the absorptionelectrode 770 exposed through the opening 99 of the organic emissionlayer 720.

In some embodiments, the metal layer as the semi-transparent layer maybe formed by depositing a Mg—Ag alloy. In some embodiments, the secondelectrode 730 is formed with a thickness of about 500 nm.

Exemplary Embodiment 1 When Forming an Absorption Electrode of a SingleLayered Structure, Absorbency Measuring According to Wavelength

The energy absorbency of the light irradiated from the energy lightsource is measured when forming the absorption electrode of the singlelayer in the organic light emitting diode display according to anexemplary embodiment of the present invention.

In some embodiments, a flash lamp is used as the energy light source.

In some embodiments, the material of the absorption electrode ismolybdenum (Mo), the absorbency is measured for the thicknesses 250 Å,500 Å, 1000 Å, and 1500 Å of the absorption electrode, and a resultthereof is shown in FIG. 14.

In the graph shown in FIG. 14, the horizontal axis represents awavelength of the light source and the vertical axis represents theenergy absorbency of the light source. As shown in FIG. 14, in theabsorption electrode of the single layer, it may be confirmed that theabsorbency of the light source energy is more than 50% in the thicknessof the absorption electrode of more than 500 Å in the visible lightregion.

Exemplary Embodiment 2 When Forming an Absorption Electrode of a SingleLayered Structure, Absorbency Measuring According to Wavelength

In the organic light emitting diode display according to anotherexemplary embodiment, the energy absorbency of the light irradiated fromthe energy light source is measured when forming the absorptionelectrode of the multiple layers.

In some embodiments, the energy light source uses the flash lamp.

In some embodiments, the material for the absorption electrode uses thedual layer of molybdenum (Mo), the thickness of the upper absorptionelectrode is 40 Å and 60 Å, and the thickness of the lower absorptionelectrode is 350 Å. The oxide layer between the upper and lowerabsorption electrodes uses ITO, and the thickness of the oxide layer isrespectively 450 Å, 500 Å, 550 Å, 600 Å, and 700 Å to measure of theenergy absorbency of the light source, and the result thereof is shownin FIG. 15.

In the graph shown in FIG. 15, the horizontal axis represents thewavelength of the light source and the vertical axis represents theenergy absorbency of the light source. As shown in FIG. 15, in theabsorption electrode of the multiple layers, it may be confirmed thatthe energy absorbency of the light source is more than 65% in thevisible light region.

The organic light emitting diode (OLED) display according to anexemplary embodiment may minimize the voltage drop of the driving powerpassing through the large-sized electrode of the thin film for drivingthe organic emission layer, and may simplify the removal process of theorganic emission layer on the auxiliary electrode by adding theabsorption electrode on the auxiliary electrode.

While one or more embodiments of the present disclosure has beendescribed in connection with what is presently considered to bepractical exemplary embodiments, it is to be understood that theembodiments are not limited to the disclosed exemplary embodiments andis intended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims.

What is claimed is:
 1. A method of manufacturing an organic lightemitting diode display, comprising: forming a thin film transistor on asubstrate; forming a first electrode connected to the thin filmtransistor and an auxiliary electrode separated from the firstelectrode; forming an absorption electrode on the auxiliary electrode;forming an organic emission layer on the first electrode, the auxiliaryelectrode, and the absorption electrode; irradiating an energy lightsource to the organic emission layer to etch the organic emission layer,thereby forming a contact hole having an opening exposing the auxiliaryelectrode and the absorption electrode; and depositing a metal layer onthe organic emission layer to form a second electrode contacting anupper surface of the auxiliary electrode, an upper surface of theabsorption electrode, and an etched surface of the opening in thecontact hole.
 2. The method of claim 1, wherein the energy light sourceis a laser, a flash lamp, or a tungsten halogen lamp.
 3. The method ofclaim 1, wherein the absorption electrode is made of one selected frommolybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr).
 4. Themethod of claim 3, wherein the absorption electrode is formed of asingle layer or multiple layers.
 5. The method of claim 4, wherein, whenforming the absorption electrode of a single layer, the absorptionelectrode has a thickness of 300-1500 Å.
 6. The method of claim 4,wherein, when the absorption electrode is formed of multiple layers, anoxide layer is further formed between the absorption electrode of themultiple layers.
 7. The method of claim 6, wherein the absorptionelectrode is formed of dual layers, and an upper layer and a lower layerof the absorption electrode respectively have thicknesses of 40-100 Åand 300-1000 Å.
 8. The method of claim 6, wherein the oxide layer is ITOor IZO.
 9. The method of claim 1, wherein the absorption electrode isformed with a line shape or a dot shape in a direction parallel to theauxiliary electrode on the auxiliary electrode.